A/C only works when car is moving?? ('99 GSX)

[slipkid]

I just noticed today when stuck in traffic that the air conditioning in my '99 GSX only blows cold air when the car is moving - if the car is just sitting still after a few minutes it is like the airco is no longer on, I only get hot sticky summer air then. If I start moving again then it instantly starts working & I get nice cool airco.

Any guesses? I'm thinking loose belt for fan perhaps? Any suggestions for things I should look at are appreciated, before I resort to taking it to a mechanic....

 

[Defiant]

How long since the system was charged? Have you looked at your sight glass?

 

[slipkid]

I don't remember ever having any A/C problems so I suspect the system has never been recharged (unless that was part of a maintenance schedule thing long ago). Since it still works ok when the car is moving I was assuming that the refrigerant level would be OK - maybe no?

I haven't looked at the "sight glass" since up to now I've never heard of it! I did some googling on the 'net & i think this must be a gauge of some sort? Perhaps this shows the level of refrigerant in the system??? Where is that/how can I measure it/look at it?? Sorry for the dumb questions, appreciate your reply but assume I know next to nothing and you'll be right.

I will do some searching up here in the threads on sight glass now though!

Thanks for your help

 

[Bud92gsx]

Yes it sounds like it's not cooling enough when in park, but then when your moving it seems to work fine...I'd say fill her up with 134-A and call it a day..

I don't think it's illeagal in your state to buy the recharge kits without a license..They cost like 20-30 $ at your local parts store...Or you can pay upwards of 70$ to have a shop do it for you...

 

[RotaryAE86]

i dont think your fan is kicking on, also the sight glass is behind the drivers side headlight on top of the receiver/drier

 

[slipkid]

Thanks guys.

I found an Eclipse service manual on-line through this thread here
http://www.dsmtuners.com/forums/fre...stions/324090-download-2g-service-manual.html

and downloaded the PDF and did some reading, I understand about the sight glass now (page 55-8 in the manual), where it is, how to use it to test refrigerant level.

I don't think I can really do the sight glass tests they are talking about on that page though, since there is already a problem when standing still (IE: if the problem is related to something like a fan belt or clutch or relay or switch or something then the results with that test may not make sense? I'm not sure).

Actually the more I read about the various tests/diagnosis that need to be done figuring out A/C problems I need a mechanic, somebody that knows what they're doing, rather than me mucking around. I'm gonna make an appt now. Thought I'd check up here first though since sometimes I have learned things that I could do myself. I appreciate the suggestions though.

 

[ApexVIII]

i assume you still have you AC fan right? maybe it is broken and not flowing air over the AC condensor?

then once you start moving it is coolign it enough? idk just a thought

 

[Defiant]

and downloaded the PDF and did some reading, I understand about the sight glass now (page 55-8 in the manual), where it is, how to use it to test refrigerant level.

I don't think I can really do the sight glass tests they are talking about on that page though, since there is already a problem when standing still (IE: if the problem is related to something like a fan belt or clutch or relay or switch or something then the results with that test may not make sense? I'm not sure).

If you're low on refrigerant at idle, higher engine speed and more airflow through the condenser will mask it some.
Pay for an AC servicing. It's a bargain.

 

[dannyd97gst]

My Eclipse does the exact same thing, suva level is good, no leaks, but the pressures are out of range. I can't remember if it was the high or low side that was out of spec (I think high side). I pulled a 15 minute vacuum on the system and it held perfectly. To make a long story short the compressor is not compressing enough at idle, higher engine speeds = more compressor speed = more pressure and cooling. I'm not into A/C enough to warrant replacing my compressor, both of my windows work.
Easy enough make sure you high speed cooling fan comes on when the a/c is in use, I doubt that is the problem though.

 

[slipkid]

I have an appt to get it checked out on Thursday. I'll post back here to let you guys know what the story is, perhaps may help someone else in the future too.

I'm hoping it is something simple like a fan belt or system just needing a recharge; if it needs a new compressor I'm guessing that will be like $500 which I can't afford right now, so I'll have to skip that option. Getting stuck in traffic in the summer heat around here is damn near intolerable without A/C though (I can't handle hot weather - I'd rather the heater break in the winter than the A/C break in the summer!!).

 

[Defiant]

To make a long story short the compressor is not compressing enough at idle, higher engine speeds = more compressor speed = more pressure and cooling.

That's also a shortcoming that 134a has compared to R-12 Freon. It doesn't cool as well. Which is why DuPont sold us Freon to begin with, until their patents were about to run out and it became a "threat" to the Corporate Profits. er, ozone layer.

 

[slipkid]

Well this is pretty frustrating.

I took the car in to the mechanic today - they are supposedly "experts" in AC problems. But they could not find anything wrong!!!! The AC worked fine for them the entire time. They checked out a bunch of things anyway including the charge, belts, etc but could not find anything wrong.

So the key now seems to be that this is an INTERMITTENT problem, and unless it is happening they can't diagnose it. I even sat in the parking lot of the garage afterwards with the motor running and AC on for 15 minutes and it ran fine for me.

Unless folks have some other ideas for something I should look at the only thing I can do at this point is wait for it to happen again & hope I am nearby that garage to bring it back (they told me that would be OK to do).

Thanks for the tips though guys. Anyone else ever have a crazy intermittent AC problem like this? I've actually only ever noticed this twice, once this past Sunday and previous to that a few months ago, but other than those 2 times I've never been just sitting anywhere idling for more than 5 minutes to know if it might be a problem or not (except today, when it kept working).

 

[TunaTalon]

My 98 Talon has a similar problem. The A/C works as long as I can keep the speed up but blows hot when puttering around town.

I paid for an A/C tune up and the refrigerant was topped off and there was no problem in the shop. On the way home the A/C stopped. The same shop checked it again and said that the fan (that should be on with the A/C) just stops intermittently. They recommended that I take it to the dealer (yeah right).
After checking the the 2g wiring diagram at http://www.dsm-club.org/doc/pdf/2g/electrical/98_ELECTRICAL_WIRING.pdf. I find that that fan is controlled by the A/C control unit.

You might ask Defiant where to find an A/C control unit. I think mine failed only because I bragged about how reliable my Talon was and Defiant challenged me to find an A/C control unit.

 

[slipkid]

You might ask Defiant where to find an A/C control unit. I think mine failed only because I bragged about how reliable my Talon was and Defiant challenged me to find an A/C control unit.

Ouch!!

 

[RotaryAE86]

i found it using that link, the text is on pg 16 and the actual diagram is on pg 17, apparently its behind the glove compartment

 

[TSiAWD666]

The car (don't know what unit controls this, if other than the ECU) will disable the a/c compressor's clutch when your coolant has reached a certain temperature. I forget what temp that is. I found this out after researching the same symptoms you were having. My cause was that my a/c fan had failed and so wasn't coming on in the designed temp range to keep coolant temps below the threshold where the compressor is disabled. So I whatever relay is triggered was getting the correct signal, just no working fan and replacing the fan fixed it.

Of course since you're having (I assume since you said it worked in recent tests) intermittent problems it's not an absolute failure which and I would say less likely the fan.

 

[Defiant]

http://www.dsmtuners.com/forums/pro...-ac-ac-brain-controller-ecu.html?highlight=ac

 

[slipkid]

Wow, amazing stuff, THANKS guys.

I have to digest that other thread, tons of info there.

Since my problem is intermittent it makes it a major pain to diagnose though. I guess at this point I am going to do nothing until it totally fails, or at least fails enough that I can count on it failing at certain times to be able to diagnose it. I have to read more in that other thread though. I wonder if that control unit thing could be the problem, just flaking out....

It's going to be %*%&ing 100 degrees here with high humidity this week so if it starts acting up now it is going to be a major motivator for me to get it fixed. I am going to try poking around under my dash to see if I can spot that control unit. Sounds like if that is the problem then it will be another hassle just to even get the part though.